p5-pdl: enabling opengl support by default breaks build on the buildbots

[dbevans (David B. Evans)]

OpenGL support in p5-pdl is provided by p5-opengl. p5-opengl builds correctly on the average workstation but fails on the buildbots because it needs to access the display to configure properly and the buildbots do not have that access. This in turn causes p5-pdl to fail and so on down the line. (My interest is p5-gimp which depends on p5-pdl and is therefore blocked).

I suggest disabling opengl support by default so that the p5-pdl build will succeed (hopefully) on the buildbots as a tool for testing and verification and (license permitting) to enable distribution of binary images of the port. A +opengl variant can be added to enable the functionality (HW accelerated 3D graphics support) if desired by end users.

FYI, here is the section of code in ${worksrcpath}/perldl.conf that can be used to disable/enable this feature

# Build Graphics/TriD using Perl OpenGL
#
# true -> use new Perl OpenGL bindings
# false -> use legacy, deprecated X11 only bindings
# undef -> let PDL build decide (check if Perl OpenGL is present)
#
        USE_POGL => undef,
#       USE_POGL => 0,

[dbevans (David B. Evans)]

Fixed in r133533, openmaintainer.

Variant +opengl added to enable opengl support, disabled by default.